Manufacture of velvet leathers



Patented Sept. 15, 1936 PATENT OFFICE MANUFACTURE OF VELVET LEATHERS John J. Callahan, Peabody, Mass, assignor to The Turner Tamiing Machinery Company, Portland, Maine, a corporation of Maine N Drawing. Application August 24, 1935, Serial No. 37,754

6 Claims.

This invention relates to the treatment of skins to secure a velvety or napped surface. While the invention is described with reference to the slicing off and removal of a thin layer from the grain surface of sheepskins while in an untanned condition as an essential feature of a new method of treatment, it will be understood that the invention and various characteristics thereof may have other applications and. uses.

Heretofore, in the manufacture of certain types of soft velvety leathers, the skins, after the unhairing operation, were subjected to treatment in a lime liquor for a relatively long period of time, as much as thirty or forty days, and then a layer of the softened grain was removed by means of a two-handled fleshing knife while the. skin was spread out over a beam. It Will be readily understood that every considerable skill was required in removing the grain evenly under these conditions. Furthermore, it was a relatively slow and laborious job. Because of the length of time in- .volved in the preparatory liming of the skins, there was also a considerable degree of expert care involved to insure against damage to the skins by putrefactive changes during such liming Altogether, the method heretofore practiced was both time-consuming and costly. Following the described preliminary treatment, which is termed frizzing by the tanners, the skins were properly tanned, usually by chrome tanning methods designed to insure a soft feeling leather. Subsequently these skins were colored and fat liquored, then dried, and lightly staked to bring up the nap.

It is an object of this invention greatly to shorten the time required in the manufacture of certain types of velvety leathers and at the same time substitute a machine operation for the hand cutting operation, by which production may be increased and costs reduced. It is a further object of the invention to produce an article of high quality and with greater uniformity in the finished product.

To these ends and in accordance with an important characteristic of the invention, untanned skins are subjected for a brief period to treat ment by which the skins, and particularly the grain surfaces thereof, are permeated to a substantial extent with a powdery substance, such as French chalk or lithopone. This treatment of the skins with a suitable powder reduces the normal slippery condition of the skins to such an extent that the feed rolls of a fleshing machine will grip the skin without undue pressure and in such manner as to insure uniform and proper feeding thereof, the skins also having the grain surfaces thereof firmed and otherwise put in a much better condition for cutting action by the blades of a fleshing machine, with the result that a thin substantially continuous layer is readily removed from the grain surface of the skin. The surface thus exposed on the skins, by the removal of a thin'layer from the original grain surface of the skins, issuch that in the tanned skin a napped effect is produced without other treatment than the usual finishing operations of coloring, fatliquoring, and staking. For the best quality work, it is desirable to buff the frizzed surface after tanning and before coloring, althrough the skins may be buffed after coloring if the latter has penetrated deeply into the skin substance;

The above and other important characteristics of the invention will now be described in detail in the specification and then pointed out more particularly in the appended claims.

In the practice of the method, sheepskins from the pickle are introduced into a drum and washed for about five minutes in fresh water to remove quite a substantial proportion of the salt and acid 5 from the skins. Then a powder such as French chalk or lithopone is introduced into the drum in a substantial amount, for example, in the proportion of about a half pound (or even more) of the powder per skin, and. the drumming is continued for about half an hour, after which the skins are drained for a short time. I have discovered that the grain portions of skins thus treated are firmed and otherwise conditioned so that a layer may be readily removed from such grain portion of the treated skin by the bladed cylinder of a machine of the well-known fleshing machine type. Such layer of the grain portion of the skin is removed by a scraping cut during the rotation of the cylinder. While it has heretofore been proposed 40 to treat skins with a fine insoluble powder to facilitate cutting operations, and more particularly fleshing operations and splitting with a band knife, as described and claimed in United 1 States Letters Patent No. 1,961,377, granted June 5, 1934, upon application of M. M. Merritt and N. H. Poor, no one so far as I am aware ever before suggested the possibility of removing a layer of the grain surface of a skin by a scraping out as herein disclosed, it being well known that the grain layer of a hide or skin is much more resistant to cutting and scraping operations than the relatively looser textured flesh surfaces of such hides or skins.

The skins after the described preliminary treatment are individually introduced into a fleshing machine, with blades properly sharpened, with the grain surface up for treatment by the blades of the bladed cylinder. Upon proper setting of the machine, a thin practically continuous layer is readily removed from the grain surface of each skin. The new surface is, of course, less dense and compact than the original grain surface of the skins. -In fact, the ends of the fibers stand up as a result of the scraping cutting effect of the blades of the cylinder, so that when the skins have been tanned, colored, andstaked,- they will be found to have a napped or velvety surface. As above indicated, the frizzed surface may be given a finer and more uniform effect by bufiing after the coloring operation.

It is to be understood that the only :liming of the skins, according to this method, is that which. is employed as a preliminary to the removal of the hair or wool and of the epidermal layer of the skins. Following; the ,runhairing or wool pulling ioperationhthe skins are degreased, fleshed, bated, ,andipickled. Conveniently, the method of treatmentabovedescribed begins with the pickled skin.

Having described my invention, what I claim as new andudesire to secure by Letters Patent of the United states is:

1. That; improvement in methods of manufacturing velvetyi leathers which comprises filling the grain .portion of an vuntanned skin-with a fine powder, thereby to firmsuch grain portion of the skin and then, cutting athin layer from the grain surface of the skin.

2. That improvement in methods of manufacturing velvety leathers which comprises filling both the grain and-flesh surfaces of, an untanned skin with a fine powder thereby to reduce very substantially ,the;.slip.pery;condition of the skin and:.to; firm..the grain surface thereof, so that thesskinimaybezproperly fed ,by the feed, mechanism of a cuttingmachine, and then while said surf aces-carry substantial amounts of suchpowder cutting a-thin layer fromthe grain surface of the skin with a; machine designed to perform cutting .operationson hidesand: skins.

3. That improvement in methods of manufactming rvelvety leathers which comprises drumminguntanned skins. in a suspension .of a fine powder until both the grain and flesh surfaces of the skins are permeated with the powder, and then removing by a scraping-slicing cut a thin layer from the grain surface of each skin.

4. That improvement in methods of manufacturing velvety leathers which comprises drum ming pickled skins in a suspension of French chalk in the amount of about one-half pound per skin until the grain surfaces of the skins are permeated with the chalk powder whereby said grain surfaces are substantially firmed by the permeated powder, and then while said grain surfaces are still permeated with the powder cutting a thin layer from the grain surface of each skin by a scraping-slicing cut.

5. That improvement in methods of manufacturing velvety leathers which comprises washing pickled skins for about five minutes to remove a substantial portion of the salt and acid therefrom, drumming the skins in a suspension of a fine :powlder until the flash -.and grain. surfaces thereof: arerpermeated with the powder, whereby the said. surfaces are firmed and rendered sub- .stantialiy less slippery-than before, and then while .said surfaces. carry substantial amounts of such'spowder, feeding theskin into a flashing machinezand cutting a thin layer from the grain surface. of each skin by a scraping-cutting operation thus frizzing the skin.

6. That improvement in. methods of manufacturing velvety leathers which comprises washing pickled skins for about five minutes to remove a substantial .portion of .the salt and acid therefrom, drumming the skins in a suspension of a fine powder until the flash and grain surfaces thereof are permeatedwith the powder, whereby the said surfaces are firmed .and rendered substantially less slippery than before, then while said surfaces. carry substantial amounts of such powder feeding the:skin into. a fleshing machine and cutting. a thinlayer from the grain surface of each skin by a scraping-cutting operation thus friz-zing the skin, then tanning and coloring the skins, and finally buffing the frizzed surface to obtain a finer and more uniformly napped surface on the finished skin.

JOHNJ. CALLAHAN.

CERTIFICATE OF CORRECTION,

Patent No. 2,054,069. September 15, 1936.

JOHN J. CALLAHAN.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 1 first column, line 18, for the word "every" read very; page 2, second column, lines 21 and 35, claims 5 and 6 respectively, for "flash" read flesh; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 5th day of January, A. D. 1937.

Renry Van Arsdale (Seal) Acting Commissioner of Patents. 

